Method for improving lubricating oils and the improved lubricating oil

ABSTRACT

A method for improving lubricating oils consisting of the steps of treating a lubricating oil with a monomer selected from the group consisting of vinyl chloride and mixtures of vinyl chloride with up to 30 percent by weight of another vinyl monomer selected from the group consisting of vinyl acetate and vinylidene chloride at a pressure of from 1 to 16 excess atmospheres and a temperature of from 10*C to 150*C in the presence of an oilsoluble free-radical-former for a time sufficient to obtain a polymer content of from 0.5 percent to 3 percent by weight based on the amount of the lubricating oil, and recovering said improved lubricating oil; as well as the improved lubricating oil having a content of 0.5 percent to 3 percent by weight of said polymer polymerized in situ.

United States Patent 1 Kretzinger et al.

1 Aug. 5, 1975 [75] Inventors: Norbert Kretzinger; Horst Kutzer;

Ludwig Schmidhammer, all of Burghausen, Germany [73] Assignee: Wacker-Chemie GmbH, Munich,

Germany [22] Filed: May 25, 1973 [21] Appl. No.: 363,993

[30] Foreign Application Priority Data May 31 1972 Germany 2226667 [52] US. Cl 252/49.6; 252/58 1.156.985 4/1958 France OTHER PUBLICATIONS Polyakov et al., Chemical Abs. Vol. 58 (1963), page 13697.

Primary Examiner-Delbert E. Gantz Assistant E.\'aminerAndrew H. Metz Attorney, Agent, or FirmI-Iammond & Littell 5 7 ABSTRACT A method for improving lubricating oils consisting of the steps of treating a lubricating oil with a monomer selected from the group consisting of vinyl chloride and mixtures of vinyl chloride with up to 30 percent by weight of another vinyl monomer selected from the group consisting of vinyl acetate and vinylidene chloride at a pressure of from 1 to 16 excess atmospheres and a temperature of from 10C to 150C in the presence of an oil-soluble free-radical-former for a time sufficient to obtain a polymer content of from 0.5 percent to 3 percent by weight based on the amount of the lubricating oil, and recovering said improved lubricating oil; as well as the improved lubricating oil having a content of 0.5 percent to 3 percent by weight of said polymer polymerized in situ.

5 Claims, N0 Drawings METHOD FOR IMPROVING LUBRICATING OILS AND THE IMPROVED LUBRICATING OIL THE PRIOR ART It is known to improve the physical as well as the chemical properties of lubricants by so-called additives. A great number of different compounds have been used, since the functions which they must perform vary considerably. For example, anti-oxidants, corrosion inhibitors, dyes and freezing point stabilizers are generally added. The commercially available lubricant oils contain mostly a number of these additives.

Furthermore, it is known to improve the properties of lubricant oils' by adding polymers or copolymers, The amounts of these polymers that can be used are frequently too small, since their solubility in the oils is mostly very limited.

OBJECTS OF THE INVENTION An object of the present invention is the development of a lubricating oil having improved properties by the polymerization in situ of a vinyl chloride monomer.

Another object of the present invention is the development of a method for improving lubricating oils consisting of the steps of treating a lubricating oil with a monomer selected from the group consisting of vinyl chloride and mixtures of vinyl chloride with up to 30 percent by weight of another vinyl monomer selected from the group consisting of vinyl acetate and vinylidene chloride at a pressure of from 1 to 16 excess atmospheres and a temperature of from C to 150C in the presence of an oil-soluble free-radical-former for a time sufficient to obtain a polymer content of from 0.5 to 3 percent by weight based on the amount of the lubricating oil, and recovering said improved lubricating oil.

These and other objects of the invention will become more apparent as the description thereof proceeds.

DESCRIPTION OF THE INVENTION The above objects have been achieved by the development of a method for improving lubricating oils which is characterized in that the lubricating oils are treated with vinyl chloride or with vinyl chloride and up to 30 percent by weight of vinyl acetate or vinylidene chloride at a pressure of l to 16 atmospheres and a temperature of 10C to 150C in the presence of freeradical-formers.

More particularly, the invention involves a method for improving lubricating oils consisting of the steps of treating a lubricating oil with a monomer selected from the group consisting of vinyl chloride andmixtures of vinyl chloride with up to 30 percent by weight of another vinyl monomer selected from the group consisting of vinyl acetate and vinylidene chloride at a pressure of from 1 to 16 excess atmospheres, or atmospheres gauge pressure, and a temperature of from 10C to 150C in the presence of an oil-soluble freeradical-former for a time sufficient to obtain a polymer content of from 0.5 to 3 percent by weight based on the amount of the lubricating oil and recovering said improved lubricating oil; as well as the improved lubricating oil having a content of 0.5 to 3 percent by weight of said polymer polymerized in situ.

The measures according to the invention have the effect that the lubricating properties of the oils are substantially improved. The monomers polymerize to polymers under the action of pressure, temperature and the free-radical-formers. These polymers are very homogeneously distributed in the oil, and thus effect an increase in the load capacity of the oils. Besides, they can be polymerized in amounts which are substantially above the solubility limit of the polymers added to the oils. Mostly, however, amounts of 0.5 to 3 percent by weight of polyvinyl-chloride or copolymers of vinyl chloride and vinylidene chloride or vinyl acetate, preferably l to 2 percent by weight, based on the oil, are sufficient to achieve the desired improvements.

The method according to the invention is carried out in a simple manner by adding the vinyl chloride and the other monomers, if any, to the oil and then commencing the polymerization. Additional amounts of monomers can be added during the polymerization, if necessary. The treatment time is mostly 10 to 120 minutes, preferably 30 to 60 minutes. Frequently, it is of advantage to mix the oil-monomer mixtures thoroughly with stirring elements. A temperature of between 30C and C is preferred. It is also possible to use the oil untreated and then to add the monomers and the freeradical-formers. The polymerization is effected in this procedure while the machine to be lubricated is in operation.

As free-radical-formers, most oil soluble polymerization catalysts can be employed, for example, peroxides, such as dilauroyl peroxide, diacetyl peroxide, di-tert.- butylperoxides: per esters, such as dialkyl peroxide dicarbonates acetylcyclohexyl sulfonyl peroxide: azocompounds, such as azoisobutyric acid dinitrile and boron alkyls. It was found, however, that other freeradical-formers, such as sterically hindered phenols, for example, 3, 6-diisopropyl-pyrocatechol, 2,6-di-tert: butyl-phenol, 2,4-di-tert.-butyl-phenol, 2,6-di-tert.-butylp-cresol, 4,6-di-tert.-butyl-o-cresol, and 2,6- diisopropyl-phenol are also suitable as free-radicalformers. Usually about 0.05 to 0.5 percent by weight, based on the. oil, are used as free-radical-formers.

When using oils which contain already free-radicalformers as additives, such as age resistors, e.g., sterically inhibited phenols, the use of additional freeradical-formers is not necessary.

The treatment according to the invention may be carried out in the presence of inert gases (up to 50 percent by volume) for example, hydrogen chloride, nitrogen, inert gases of the argon group, and in some cases oxygen.

The method is applicable for various oils. Preferably it is used for mineral lubricating oils of varying composition and viscosity and for silicone oils, for example, methyl-and optionally halogenated-phenyl silicone oils. Examples of other synthetic lubricating oils are: monoand diesters, polyesters, glycols, polyglycols, polyalkylene-glycols, polyformals, chlorinated diand terphenylene chlorinated'paraffins, alkyl'-, arylor alkylaryl-phosphoric acid esters. Blends of these oils can also be used.

The normally used additives (e.g., 0.01 to 2 percent by weight) can be added to the oils before or after the treatment. Examples of these additives are: flow point reducers, viscosity index improvers, agents producing fluorescence, corrosion inhibitors and agents improving the oiliness. Suitable substances of this type are, for example, paraffin-napthalene-condensation products, inorganic and organic nitrates, as well as organic phosphites, phosphates and phosphonates. Phosphorus sultide-olefin reaction products, metal-organic phosphates, organic sulfides or amines can also be used. Furthermore, anti-oxidants, age resistors, dyes, emulsifiers, detergents, foam suppressants, bactericides, disinfectants and water-repelling substances can also be added to the oils.

The following examples are illustrative of the invention without being limitative in any respect.

The so-called Almen-Wieland lubricating test was used to determine the load bearing lubricating properties. To this end a Wieland-lubricant testing machine (manufacturer: Max Wieland, Krottenmuehl-Simsee,

4 cent acetylcyclohexylsullonyl peroxide was treated according to Example I (PVC-content after polymerization-1.5 percent by weight). The Almen-Wieland test yielded a pin rupture likewise at 18 atmospheres.

COMPARISON TEST The corresponding test with untreated oil led to a pin rupture at 5 atmospheres.

EXAMPLE 3 A gas that consisted of 50 parts of vinyl chloride and 50 parts of hydrogen chloride was introduced at 60C and 1.5 atmospheres into 50 liters of BP oil, Energol Upper Bavaria, Germany,) was used. The measuring 5 LPT 80, a mineral oil having a viscosity of 35 cSt at TABLE Amount of vinyl chloride Pressure by Pin dissolved Temp. in atmoweight rupture Test No. Oil in by weight Free-radical-former "C spheres PVC atmosphen 1 CS 100 O 20 l 2 2 CS 100 0 40 L5 0 2 3 CS I00 2 0.1% by weight of 80 l 2 l6 lauryl peroxide 4 CS 100 I5 0.1% by weight of 60 5 2.5 18

lauryl peroxide 5 CS I00 0.1% by weight of 60 l 0 2 lauryl peroxide 6 CS 100 0.1% by weight of l 0 2 di-tert.-butylp-cresol 7 CS I00 3 0.1% by weight of 60 1 0.8 I0

di-tert.-butylp-cresol 8 cs 100 5 0.5% by weight of 80 2 1.1 12

di-terL-butyL p-cresol prmclple based on the fact that, y exertmg Vafi- 50C, which contained 0.1 percent by weight of benbly ncreasing pressure on a bearing WhlCh is lubrizoyl peroxide. 1.73 percent by weight of vinyl chloride cated with the Oil to be tested, the point can be deter- 40 d ()3 ent by weight of hydrogen chloride di mined at which the pin breaks, that is, at which the bearing seizes up due to inadequate lubrication.

All pressures reported are atmospheres gauge or excess atmospheres.

EXAMPLE 1 COMPARISON TEST The untreated BP oil, Energol LPT 50 was likewise subjected to the Almen-Wieland test. The pin broke at 5 atmospheres.

EXAMPLE 2 50 liters Mobil oil DTE EXT, a mineral oil having a \iscosity of 7.05 cSt at 50C. which contained 0.5 persolved. After a treatment of 2 hours, the unreacted gases were distilled off. A content of 1.0 percent by weight of PVC was dissolved in oil. The Alman- Wieland test yielded a pin rupture at 17 atmospheres. COMPARISON EXAMPLE With a corresponding untreated oil, the pin broke at 5 atmospheres.

EXAMPLE 4 1 percent by weight of a low-molecular-weight polyvinyl-chloride (Vinnol VH 50 D, K-value 50, manufacturer Wacker Chemie) was dissolved in 1 liter of the same BP oil, and subjected to the Almen-Wieland test. The rupture occurred at 3 atmospheres.

EXAMPLE 5 One liter of silicone oil AK 500 (trimethyl-endblocked dimethyl polysiloxane 500 cSt at 25C, manufacturer Wacker Chemie) was treated for 1 hour at 80C and 1 atmosphere in the presence of 0.1 percent by weight ol'lauroyl peroxide. ith vinyl chloride After distilling off the volatile components. the oil contained lit) percent by weight of PVC, Pin rupture according to the Almen-Wieland test occurred at 12 atmospheres.

COMPARlSON TEST With a corresponding untreated oil. pin rupture occurred already at 4 atmospheresv The preceding specific embodiments are illustrative of the practice of the invention. It is to be understood, however, that other cxpedients known to those skilled in the art. or disclosed herein, may be employed without departing from the spirit of the invention or the scope of the appended claims.

We claim:

I. A method for improving lubricating oils consisting of the steps of treating a lubricating oil with a monomer selected from the group consisting of vinyl chloride and mixtures of vinyl chloride with up to 30 percent by weight of another vinyl monomer selected from the group consisting of vinyl acetate and vinylidene chloride at a pressure of from 1 to 16 atmospheres gauge pressure and a temperature of from C to 150C in the presence of an oilsoluble free-radical-former for a time sufficient to obtain a polymer content produced in situ of from 0.5 to 3 percent by weight based on the amount of the lubricating oil, and removing unreacted material.

2. The method of claim 1 wherein said lubricating oils are selected from the group consisting of mineral lubricating oils and silicone lubricating oils.

3. The method of claim 1 wherein said treatment is for 10 to 120 minutes at a temperature of from 30C and C.

4. In the method of improving the load carrying capacity of a bearing surface comprising contacting said bearing surface with a lubrication agent containing an additive, and applying a load to said bearing surface prior to, simultaneously with or subsequent to said contacting with said lubrication agent containing said additive; the improvement which consists in utilizing a lubricating oil containing from 0.5 to 3 percent by weight of a polymer produced in situ as produced by the process of claim 1, as said lubrication agent.

5. The method of claim 1 wherein said monomer is vinyl chloride. 

1. A METHOD FOR IMPROVING LUBRICATING OILS CONSISTING OF THE STEPS OF TREATING A LUBRICATING OIL WITH A MONOMETER SELECTED FROM THE GROUP CONSISTING OF VINYL CHLORIDE AND MIXTURES OF VINYL CHLORIDE WITH UP TO 30 PERCENT BY WEIGHT OF ANOTHER VINYL MONOMETER SELECTED FROM THE GROUP CONSISTING OF VINYL ACETATE AND VINYLIDENE CHLORIDE AT A PRESSURE FROM 1 TO 16 ATMOSPHERES GAUGE PRESSURE AND A TEMPERATURE OF FROM 10*C TO 150*C IN THE PRESSURE OF AN OIL SOLUBLE FREE-RADICAL-FORMER FOR A TIME SUFFIIENT TO OBTAIN A POLYMER CONTENT PRODUCED IN SITU OF FROM 0.5 TO 3 PERCENT BY WEIGHT BASED ON THE AMOUNT OF THE LUBRICATING OIL, AND REMOVING UNREATED MATERIAL.
 2. The method of claim 1 wherein said lubricating oils are selected from the group consisting of mineral lubricating oils and silicone lubricating oils.
 3. The method of claim 1 wherein said treatment is for 10 to 120 minutes at a temperature of from 30*C and 100*C.
 4. In the method of improving the load carrying capacity of a bearing surface comprising contacting said bearing surface with a lubrication agent containing an additive, and applying a load to said bearing surface prior to, simultaneously with or subsequent to said contacting with said lubrication agent containing said additive; the improvement which consists in utilizing a lubricating oil containing from 0.5 to 3 percent by weight of a polymer produced in situ as produced by the process of claim 1, as said lubrication agent.
 5. The method of claim 1 wherein said monomer is vinyl chloride. 